The invention relates to a method and apparatus for obtaining relevant traffic information and for dynamic optimization of a route of vehicles pertaining to a self-organizing traffic guidance system in accordance with the preambles of claims 1 and respectively, and in particular to a method for a self-organizing system for traffic guidance, signaling traffic disturbances and extraction of statistical data, as well as to a method for efficient, purposeful dissemination of third data in an information network under formation.
Previous methods or devices for traffic guidance to a large extent rely on an external, fixedly installed traffic detection or on central information processing, respectively.
In order to increase the rate of vehicles passing through a particular traffic section and thus to increase the mean velocity of the vehicles in particular in the event of an elevated traffic volume, conventional traffic guidance systems have already been fixedly installed along traffic sections particularly that are subject to particularly intense utilization such as, for example, heavily frequented highways etc. The like conventional, fixedly installed traffic guidance systems possess a multiplicity of detection devices detecting, for example, traffic density, the velocity of the flow of vehicles, the environmental conditions such as, e.g., temperature or fog, etc., and by means of the respective detection signals control vehicle traffic along the predetermined amended documents section with the aid of indicator panels, such that a uniform traffic flow having a maximum possible velocity is created.
One drawback in such conventional traffic guidance systems is their fixed installation along a predetermined road section, resulting in extraordinarily high purchasing costs. In addition, such a fixedly installed traffic guidance system only has low flexibility as it exclusively controls or guides traffic in relatively short sections.
In order to enhance flexibility, U.S. Pat. No. 4,706,086 proposes a communication system between a multiplicity of vehicles, wherein signals and information are transmitted in accordance with the respective running conditions of the vehicle via a a transmitter/receiver unit with the aid of electromagnetic radio waves.
Moreover from U.S. Pat. No. 5,428,544 a device and a method for signalling local traffic disturbances are known, wherein the vehicle data or running conditions of the vehicle such as, e.g., the speed, the route and the direction are mutually transmitted via communication means. Transmission of the respective data to another vehicle is herein achieved in an indirect manner by way of an oncoming automobile.
A method and apparatus in accordance with the preambles of claims 1 and 58, respectively, is known from DE-A-40 34 681.
In the former traffic guidance systems, the vehicle data are either detected in a locally limited area by fixedly installed equipment and are only available locally, or they are detected in a large area by a plurality of mobile means, but are relayed with such a low degree of efficiency as to also be only available locally, wherein the planning or optimization of a route of vehicles beyond a local area with consideration of traffic-relevant quantities of the entire travelling distance is not supported. It is, however, not known to dynamically obtain relevant traffic information.
The invention is therefore based on the object of furnishing a method and apparatus for dynamically obtaining relevant traffic information, wherein relevant traffic information is created in a second location which may be at any distance whatsoever from a first location, and is efficiently relayed to the first location.
In accordance with the invention, this object is attained through the measures and features of claims 1 and 58.
Further advantageous developments are the subject matters of the dependent claims.
The method of the invention for dynamically obtaining relevant traffic information and for dynamic optimization of a route of a first vehicle pertaining to at least one self-organizing traffic information system and traffic guidance system to which further vehicles pertain, includes the following steps performed by the first vehicle: creating own data on the basis of at least one of on-board sensors and other information sources in the first vehicle; emitting data that are relevant for the first vehicle or for other, corresponding to a broadcast; receiving data transmitted by other vehicles; storing data obtained from at least one of received and own data; creating and transmitting inquires concerning data which may be furnished by other vehicles, corresponding to a request; and relaying of received data by re-transmission of these data in a processed or unprocessed form, corresponding to a replication.
Thus the method according to the invention in principle allows for an autonomous, self-organizing traffic information network in which the participating vehicles at the same time generate, distribute, bundle and utilize the required information.
The method operates in a particular scale-invariant manner, i.e. fractal-hierarchical manner, so that with respect to the type of processing and with respect to the communication volumexe2x80x94at least with regard to dynamic route optimization and signalling of traffic disturbances which constitutes a safety aspectxe2x80x94it is not of importance what order of distances is aimed at.
The method is operable on highway networks just like in a street network of a large city.
In particular the communication volume scales well, i.e. xe2x80x9c less than n*log nxe2x80x9d, with the overall number of participating vehicles and the surface of the area.
Despite the fundamental autonomy of the system, however, centrally generated information may also smoothly be routed into the system, and information may also be extracted from the system, e.g. for statistics purposes, and compiled centrally.
An enormous advantage in terms of costs, optimum efficiency, a high degree of failure safety and at the same time a bundled increased value as well as a unified user interface are thus achieved in comparison with existing methods. At a high degree of implementation, this system may in addition be used as a safety system.
Besides, the network formed through the instant method also offers an extremely efficient platform for the transmission of third data up to mobile telephony. It is even readily possible to enhance effectivity of the resulting communication network through utilization or smooth integration of a backbone line network.
In particular the method and apparatus of the instant invention might have the following further features.
Inquiries might be answered, partly answered, relayed and/or partly relayed, corresponding to a response and a replication.
Answering inquiries and/or handing on inquiries and other data are performed by vehicles having a suitable/optimum information status or having a favorable/optimum current position for relaying, whereby an optimization of answering and relaying is achieved.
In steps [a] and [d] of the method, travel history data are additionally created by the vehicles, whereby the significance of the data is increased.
In steps [b] and [c] of the method, a source group of vehicles associated with the first vehicle are designated for receiving data from respective vehicles; herein the data may be stored, accumulated and preprocessed in the receiving vehicles for the purpose of generating source data for the subsequent steps, corresponding to a first source formation.
In preprocessing the source data, mean velocities, maximum velocities, traffic density measures, backup sensitivities, bundled up-to-dateness measures and/or bundled relevance measures may be calculated, corresponding to a second source formation.
Designation of the group of vehicles is performed by designating an adjustable transmitting field strength or transmitting range of the first vehicle, thereby defining a first transmitting range.
The adjustable transmitting field strength is controlled such that on the average a predetermined criterion with respect to a parametrizable number of vehicles within reach is satisfied, thereby defining a second transmitting range.
The transmitting field strength control may incorporate positions and employed transmitting field strengths of neighboring vehicles encoded into the received signals, thereby defining a third transmitting range.
The route of the first vehicle from its current position to a selected target is determined by means of stored way data, and the route is subdivided into way segments.
The first vehicle can transmit inquiries for information relating to a practicability and other traffic-relevant quantities on candidate way segments to be travelled later on.
Replies to inquiries by the first vehicle are returned to the first vehicle directly or via relaying, wherein the information in the replies may also be received, stored, accumulated and processed for suitable further use by transmitting vehicles and by vehicles which also receive the replies, corresponding to a caching and a utilization.
The travel history data, source data, buffer memory data which in particular contain the stored, accumulated and processed information, and reply data in the vehicles may each be stored in an individual map structure superseding a static global map structure or existing in parallel therewith.
From running condition data, travel history data and/or data obtained by combining running data of several vehicles, it is possible to also create, modify or delete new map structure elements in the individual map structure data, and also extract them from the traffic guidance system for external utilization.
For purposes of internal processing and referencing in transmission signals, a subdividing of the individual map structure into way segments satisfying a predetermined criterion with regard to a length is performed, corresponding to a first map representation.
Combining way segments of the individual map structure is carried out for purposes of internal processing and referencing in transmission signals into groups and superordinate groups each having their own identifications, corresponding to a second map representation, or a compression through hierarchy formation.
A first calculation of the route of the first vehicle from its current position to a selected target may be carried out with the aid of statically stored or already available dynamic distance data, corresponding to a static or dynamic routing.
A recalculation of the route may be carried out based on modified data in the individual map structure for the purpose of iterative optimization of the route.
In creating inquiries, a desired up-to-dateness may be encoded into die inquiry, corresponding to an update request.
Answering an inquiry may be carried out, depending on a desired up-to-dateness, from source data of vehicles in the vicinity of the target area of the inquiry, or from buffer memory data in particular containing the stored, accumulated and processed information, of vehicles far removed from the target area and closer to the inquiring vehicle, so that the number of instances of relaying inquiries may be kept low, corresponding to a cache utilization.
A favorable vehicle from among the group of vehicles which is capable of answering and/or relaying the inquiry, may be determined through an evaluation method wherein an evaluation measure is determined in dependence on the up-to-dateness or a relevance of data already available to the respective vehicle and concerning way segments in question, the number of inquiries which can be answered on the basis of already available data, and/or the distance of the respective vehicle whose inquiry cannot be answered from the next way segment, corresponding to a first delay routing.
In dependence on the evaluation measure, a delay period for emitting a reply and/or relaying may be set which becomes shorter with an increasing evaluation measure, so that vehicles are enabled to transmit earlier with a better evaluation measure, corresponding to a second delay routing.
A particular vehicle with an intention to transmit concerning a reply to an inquiry and/or relaying an inquiry with respect to a particular inquiry characterized by an action code may stop the intended emission if it receives a signal concerning the same inquiry and having the same action code from another particular vehicle which has preceded the particular vehicle due to a shorter delay period.
An assessment is carried out whether for a particular way segment an inquiry is to be created, corresponding to a calculation of a first necessity of inquiry. Hereby the communication volume is reduced.
The assessment whether an inquiry is to be created for a particular way segment is carried out in dependence on the distance of the way segment from a current location of said first vehicle, the estimated time until arrival at the way segment, a weighting factor of the way segment, a backup frequency known from the past and/or the up-to-dateness of already available data relating to the way segment, corresponding to an evaluation of a second necessity of inquiry.
Transmitted data may include information concerning a signal type, a vehicle identification, the utilized transmitting field strength, a location of the vehicle, an unambiguous action code, as well as a list of identifications of previously used transmitter vehicles in the form of a history list, whereby first information contents are defined.
Transmitted data may moreover include information concerning way segment identifications, a moving direction, a proportion of a covered way segment, a mean velocity, a maximum velocity, the vehicle density, and/or a up-to-dateness/time marking of the information, whereby second information contents are defined.
Handing back a reply to an inquiry may be carried out by using the history list, corresponding to a first handing back or utilization of the history list.
Handing back a reply to an inquiry by a relaying method may furthermore take place in analogy with forwarding the inquiry, corresponding to a second handing back or to a renewed routing, respectively.
The first vehicle creates and transmits a plurality of inquiries relating to single way segments, which are each individually answered and/or relayed as well as returned with a reply, or an inquiry relating to the entirety of way segments, wherein the inquiry relating to the entirety of way segments includes a plurality of partial inquiries relating to single way segments, which are successively answered or relayed by the vehicles of a chain of transmitter vehicles, corresponding to a combination of inquiries.
One or several groups of vehicles are formed which are each in possession of data of particular neighboring way segments, with group relevant data common to respective vehicles being available such that an inquiry concerning data of such groups may be answered by each vehicle of the group, or answering may be effected through few instances of relaying, corresponding to a first source hierarchy formation.
From the groups one or several superordinate groups are formed which are each in possession of data of particular neighboring way segments, wherein supergroup-relevant data common to the respective vehicles are available, such that an inquiry concerning data of such superordinate groups may be answered by each vehicle of the superordinate group, or answering may be effected through few instances of relaying, corresponding to a second source hierarchy formation.
Vehicles of the group create and transmit data containing information relating to a position, extension and minimum lifetime of the group, corresponding to a third source hierarchy formation by means of a group protocol.
Group data may contain mean velocities, maximum velocities, vehicle density measures, up-to-datenesses/time markings and/or information relevance measures with respect to the entirety of the vehicles of the group, corresponding to a fourth source hierarchy formation by means of group data.
Group formation may moreover take place in that group formation applications by one or several vehicles or subgroups are accumulated, and in that the actual group formation is only determined when a threshold is exceeded, corresponding to a fifth source hierarchy formation by means of a group formation.
To a vehicle or to a group of vehicles external data are supplied for directional or non-directional handing on, wherein a group formation may also be brought about through these external data, corresponding to supplying external data to vehicles and groups.
The external data may contain information relating to a backup prognosis, corresponding to an external prediction.
Information relating to a backup prognosis or other traffic-relevant quantities is extracted and stored externally, wherein it is also possible to cause a group formation from inside or from outside of the system in order to obtain the relevant quantities, corresponding to an extraction of traffic data.
The external data contain information relating to connectivity with other traffic systems, such as railway, subway, urban railway, air and/or boat traffic, whereby an intermodal traffic is defined.
Information relating to a backup prognosis due to events detected in the past and occurring cyclically is generated from vehicle data signals and transmitted, wherein group formation may also be initiated for the purpose of cyclic backup prognosis, corresponding to a periodical prediction.
Information relating to a backup prognosis due to events detected in the recent past is generated from vehicle data signals through extrapolation of the traffic flows or simulation and transmitted, wherein group formation may also be initiated for the purpose of simulative backup prognosis, corresponding to a simulative prediction.
Information relating to a backup prognosis and/or other traffic-relevant quantities is stored within a group of vehicles to be designated and continues to exist there.
Data relating to a dangerous approach of the first vehicle to another vehicle pertaining to the traffic guidance system or to a group pertaining to the traffic guidance system is generated and/or transmitted, whereby a safety system is defined.
Handing back of inquiries that have not been answered takes place in the form of specially marked pseudo-replies, whereby a first pseudo-reply is defined.
The fact that a relayed inquiry has not been answered may moreover be detected in that when an inquiry is relayed by a particular vehicle, emission of a pseudo-reply is concurrently determined with a high delay time, whereby a second pseudo-reply is defined.
Emission of the pseudo-reply from the particular vehicle may be stopped in that another particular vehicle located within reach of the particular vehicle in its turn answers or hands on the relayed inquiry, which fact may be recognized by the particular vehicle on account of an action code of the inquiry, whereby a third pseudo-reply is defined.
Information is combined upon return of replies to inquiries or upon intermediate storage in transmitter vehicles, so that data from a greater distance may be compressed more strongly/resolved more roughly by an inquiring party, corresponding to an integration.
Emitted data signals are relayed, in analogy with processing inquiries, both along a one-dimensional channel up to a target location and also two-dimensionally into a more extended target area encoded into the data signal, corresponding to a further integration.
Data signals contain information which, on account of a particular event, is created by a vehicle and transmitted directionally or non-directionally, corresponding to an event broadcast.
The vehicles are land vehicles for road or rail traffic, water vehicles, aircraft or other mobile, manned or unmanned units moving in a jointly utilized traffic space and capable of being equipped with limited-range communication means.
Vehicles may also be particular pseudo-vehicles having a special communicative purpose of sending data signals out of the traffic guidance system or into the traffic guidance system, feeding in third data, need not necessarily be mobile, but at least are equipped with compatible communication means.
Via a pseudo-vehicle or a station a connection with another telecommunications network is established.
Pseudo-vehicles or stations are created which are linked among each other by an external communication network and establish a more favorable mutual connection of said vehicles or between said vehicles and a transmitter/receiver located outside the traffic guidance system, whereby a backbone network is defined.
By the communication means of the vehicles and/or the pseudo-vehicles/stations a telecommunications network is formed.
In accordance with the invention, an apparatus for determining and optimizing a route of a first vehicle pertaining to a traffic guidance system to which further vehicles pertain is created, including: detection means for detecting local vehicle data to be transmitted; transmitter/receiver means for transmitting/receiving radio signals containing respective vehicle data to be transmitted/received; intensity adjusting means for freely adjusting a particular transmitting field strength up to a maximum transmitting field strength; intensity detection means for detecting the intensity of the respective received radio signals; storage means for storing data; group designating means for designating a group associated with the first vehicle following reception of the vehicle data of the respective vehicles; route determining and segmenting means for determining, with the aid of stored distance data, a route of the first vehicle from its current position up to a selected target and subdividing it into way segments; and route optimization means for making an inquiry concerning vehicle data containing information relating to practicability of the respective way segments to the group of vehicles and determining an optimized route by means of vehicle data received in response to the inquiry. By the above described features a structure of an intelligent communication device is created.
Moreover delay period signal generation means may be contained for emitting a data signal only after lapse of the determined delay period in dependence on a freely determinable time delay value, whereby a first delay generation takes place.
Moreover control means may be contained, whereby emission of the delayed data signal may subsequently be stopped prior to lapse of the delay period, whereby a second delay generation takes place.